Please measure your posts before purchase! Sun Powered No Wiring On/Off switch Ultra Bright LED Powered by the sun Fast & easy install Rechargeable Ni-Cd AA battery included Energy, electrical saving Ideal for areas where conventional electrical supply is not available One High output long lasting ultra-bright white LED bulb More expensive ultra-highly sensitive solar panel usually seen on calculators is used Automatic dusk-to-dawn operation, On/off manual over-ride switch Recharged by solar panel under sunlight Light turns on automatically when dark Safe Water Resistant Corrosion resistant CE certified - User controllable on / off switch - CE Certified for ultimate safety - WILL FIT 4" x 4" POSTS Solar Light Dimensions : 5.5" (l) x 5.5" (w) x 4.5" (h) *** Post Size Fitting *** - Wood or Composite Posts : must be smaller than 3-13/16" square - Hollow Vinyl Posts : inside opening must be larger than 3-15/16" square